1. Technical Field
The present invention relates generally to printing, scanning and document authentication technology, and in particular to a method and system for generating and authenticating documents using stored electrostatic patterns.
2. Description of the Related Art
Document authentication technologies are increasingly in-demand as technologies for counterfeiting improve. Further, due to the ease of document alteration possible with today's computer document processing tools, needs for verification that a document is an unaltered original are also continuously increasing.
Existing technologies for verification include microscopic watermarks and magnetic ink patterns such as those used on currency and bank notes. A pattern that is not visible to the human eye or not visible without proper detection devices is more difficult to duplicate and/or alter. Technologies to thwart the security measures afforded by existing technologies emerge as those technologies are implemented or improved upon.
Applications of the above-mentioned security patterns are generally provided in automated printing process, but it would be useful to provide for such processes with respect to handwritten instruments. However, the technology required to implement “hidden” patterns within a document typically has a high cost that makes it prohibitive to incorporate watermarking or magnetic marking techniques within a handheld device such as a pen.
Similarly, it is typically not cost-effective to incorporate the above-described security marking techniques within a low-cost printer, as to be effective, a microscopic watermark must not be renderable by a typical photo-copier or printer and a magnetic marking process typically requires a second pass with a special device that magnetizes domains within the magnetic ink.
U.S. Pat. No. 6,530,602 discloses including machine-readable patterns of an invisible substance including binary patterns or bar codes that are printed on a document and later used to verify authenticity. The substance has physical properties that are detectable via machine, such as luminescent, magnetic, electroconductive or other mechanical properties. However, the above-referenced patent discloses only the presence or absence of an applied substance and does not contemplate application of electrostatically-detectable substance, nor a system for the production and verification of handwritten documents.
It is therefore always desirable to provide new methods and systems for document authentication. It is further desirable to provide such methods and systems having a low associated cost. It is also desirable to provide such methods and systems that can be applied to handwritten documents.